Weather instruments, or meteorological instruments, are the equipment used to sample the state of the atmosphere. Meteorologists use a wide variety of different instruments to measure weather conditions. These instruments fall into common categories. Thermometers, for instance, come in liquid-in-glass forms and electronic forms, but both measure temperature in Celsius and Fahrenheit. Other instruments measure rainfall, pressure, humidity and wind speed. Meteorologists can then make predictions on weather conditions in the near future. Weather instruments include: Thermometers, barometers, hygrometers, anemometers, pyranometers, rain gauges, precipitation sensors, disdrometers, transmissometers, and ceilometers.